How were medieval navy commanders able to communicate with 100’s of ships during war?


During medieval navy wars, there was a lot of smoke and noise from cannon fire. The weather was sometimes stormy. The visibility and sound wouldn’t have been that good. How were they able to command ships during such conditions and keep updated with rapidly changing events during battle?

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Using signal flags. A pair of flags used by a signaller in different positions can be used to spell out the alphabet

>medieval navy wars

Didn’t happen a lot. Naval warfare mostly happened earlier (roman times) or later (post rennaisance)

But in general they didn’t communicate well. They used flags for signalling, but even in WW1 miscommunications were still very common. So everything basically boiled down to whose pre-battle plan fitted the conditions of the actual battle better.

Most of the communication was done with signaling flags. Either they would hoist a string of various flags up in the mast where each flag represents a character but often a special signal determined beforehand. You could also have sailors standing on deck waving two flags like a semaphore. Sometimes the ships would be close enough that in a silent moment the captains could shout to each other.

But a lot of it was down to organization beforehand. Each captain would be responsible for their own ship and make decisions based on what they observed and what the plans were before the battle. A common tactic was to fight in a line with the Admiral in the front. The stern of one ship would be close to the bow of the next making it easy to pass orders down the line. So the line of ships could maneuver and fight like one. If they had to quickly turn around there was a Rear Admiral at the rear of the line who could take over command and lead the line.

The main ship of the fleet where the person in charge of the fleet resides (today an admiral) is called the “Flagship” because ships communicated with literal flags.

There would be a codebook with quick messages and an agreed set of quick signals to tell the fleet things like “withdraw”. The Flagship needs a generalized plan, but for the most part ships are too slow to respond quickly especially when the brawls start happening so once the battle is going its a series of much smaller 1v1 and 1v2 engagements that go until they’re done or the Flagship requests a withdrawal.

Fleet battles were also relatively small, Trafalgar in 1805 was 73 ships in total. Every ship picked a target and pretty much just dueled that one. The Battle of Lepanto in 1571 is probably the fight with the most mid/large ships with about 400 galleys total but galleys are pretty small and only have like 2-8 cannons so there isn’t much smoke and each ship has relatively limited combat capabilities so nothing changes abruptly

Captains of ships end up with a lot of liberties in the actual tactical decisions because they are so isolated and so restricted in movement that its impractical to try to micromanage the battle, the ships can’t effectively respond to commands in less than a few minutes.

Judging by your description, I think you’re talking about the age of sail. ie. big sailing ships loaded with cannons. Those weren’t the medieval days but the between the 16th and 18th century.

Secondly, those engagements weren’t as big as you think. Most were skirmishes between hands full of ships or tens of ships at most. The biggest naval engagements still numbered less than 100 ships total.

But you’re right, communication is hard in those conditions. That’s why it required clear roles, clear plans and clear chains of command.

The ships themselves had roles. A ship of the line is basically a floating bunker filled with cannons. Astounding firepower but not much speed or manoeuvrability. That ship has a very clear idea of what it can and cannot do.

A frigate is a warship build for speed. They’re much faster and more agile and their role was defined around that. On their own, frigates made fantastic patrol ships that could easily chase down merchant ships and pirates while outgunning them.

In larger fleets, those frigates would act as scouts. And in larger battles, a frigate would either engage opposing frigates or act as a signal ship. That means the frigate maintains a position outside the battle where it maintains line of sight with its fleet commander and the rest of the fleet.

When the fleet commander raises signal flags. The frigate will repeat those signals to the rest of the fleet. Cannon smoke might obscure the command ship and opposing ships. But a frigate could sit out to the sides where friendly ships could easily see them and their repeated signals.

It was actually considered very bad form for a large ship of the line to fire upon a smaller ship like a frigate. It’s simply unsporting.

A plan is of course also very helpful. When a fleet goes into battle, it has a goal. Stop an enemy fleet, sink a particular ship, capture a particular enemy, wholesale destruction, break through a blockade. Everyone goes into battle knowing the plan and knowing what their role in the plan is.

That means that while the battle develops, each captain can evaluate the situation and adapt their tactics to best serve their role in the plan.

This is a big part of why we romanticize captains so much. These men were not just the absolute law on their ships. They were also solely responsible for figuring out how to fulfil their duty under punishing conditions. Whether that’s complete isolation in the middle of the ocean or during the chaos of battle. A captain had to find a way to perform his duty no matter what and with little to no support or communication at times.

It’s also why you see captains and their officers on the rear deck peering about with their monoculars all the time in movies. Sailing ships move with the wind and tides. They can’t just reverse direction. That means that it’s of paramount importance for a captain to try and predict their opponents so they can outsmart and thus outsail them. They’re constantly looking at the opposing ships, how their sails are set, what their men are doing to their rigging to try and predict how to best sail his own ship.

And at the end of the day, sailing battles weren’t nearly as fast as you think they are. Ideally, sailing ships wanted to manoeuvre into a better firing position than their opponent and then quickly and decisively end that engagement. Ideally without destroying the opposing ship because it represents a valuable prize.

But outside of enormous fleet actions where ships of the line just line up and batter away at each other, most naval engagements were more like games of cat and mouse between individual ships or smaller fleets.

Ships could chase each other for hours or even days trying to get the upper hand on each other. And a lot of the time, military ships spend their time chasing down opposing merchantmen or pirates. Ships either escaped or surrendered. There’s not much point in trying to trade broadsides with a frigate if you’re sailing a sloop.